Electro Magnetic Induction- Theraja
C H A P T E R
Learning Objectives
➣ Relation Between Magnetism and Electricity ➣ Production of Induced E.M.F. and Current ➣ Faraday’s Laws of Electromagnetic Induction ➣ Direction of Induced E.M.F. and Current ➣ Lenz’s Law ➣ Induced E.M.F. ➣ Dynamically-induced E.M.F. ➣ Statically-induced E.M.F. ➣ Self-Inductance ➣ Coefficient of Self-Inductance (L ) ➣ Mutual Inductance ➣ Coefficient of Mutual Inductance ( M ) ➣ Coefficient of Coupling ➣ Inductances in Series ➣ Inductances in Parallel
7
ELECTROMAGNETIC INDUCTION
The above figure shows the picture of a hydro-electric generator. Electric generators, motors, transformers, etc., work based on the principle of electromagnetic induction
298
Electrical Technology
7.1. Relation Between Magnetism and Electricity
It is well known that whenever an electric current flows through a conductor, a magnetic field is immediately brought into existence in the space surrounding the conductor. It can be said that when electrons are in motion, they produce a magnetic field. The converse of this is also true i.e. when a magnetic field embracing a conductor moves relative to the conductor, it produces a flow of electrons in the conductor. This phenomenon whereby an e.m.f. and hence current (i.e. flow of electrons) is induced in any conductor which is cut across or is cut by a magnetic flux is known as electromagnetic induction. The historical background of this phenomenon is this : After the discovery (by Oersted) that electric current produces a magnetic field, scientists began to search for the converse phenomenon from about 1821 onwards. The problem they put to themselves was how to ‘convert’ magnetism into electricity. It is recorded that Michael Faraday* was in the habit of walking about with magnets in his pockets so as to constantly remind him of the problem. After nine years of continuous research and experimentation, he succeeded in producing electricity by ‘converting magnetism’. In 1831, he formulated
Learning Objectives
➣ Relation Between Magnetism and Electricity ➣ Production of Induced E.M.F. and Current ➣ Faraday’s Laws of Electromagnetic Induction ➣ Direction of Induced E.M.F. and Current ➣ Lenz’s Law ➣ Induced E.M.F. ➣ Dynamically-induced E.M.F. ➣ Statically-induced E.M.F. ➣ Self-Inductance ➣ Coefficient of Self-Inductance (L ) ➣ Mutual Inductance ➣ Coefficient of Mutual Inductance ( M ) ➣ Coefficient of Coupling ➣ Inductances in Series ➣ Inductances in Parallel
7
ELECTROMAGNETIC INDUCTION
The above figure shows the picture of a hydro-electric generator. Electric generators, motors, transformers, etc., work based on the principle of electromagnetic induction
298
Electrical Technology
7.1. Relation Between Magnetism and Electricity
It is well known that whenever an electric current flows through a conductor, a magnetic field is immediately brought into existence in the space surrounding the conductor. It can be said that when electrons are in motion, they produce a magnetic field. The converse of this is also true i.e. when a magnetic field embracing a conductor moves relative to the conductor, it produces a flow of electrons in the conductor. This phenomenon whereby an e.m.f. and hence current (i.e. flow of electrons) is induced in any conductor which is cut across or is cut by a magnetic flux is known as electromagnetic induction. The historical background of this phenomenon is this : After the discovery (by Oersted) that electric current produces a magnetic field, scientists began to search for the converse phenomenon from about 1821 onwards. The problem they put to themselves was how to ‘convert’ magnetism into electricity. It is recorded that Michael Faraday* was in the habit of walking about with magnets in his pockets so as to constantly remind him of the problem. After nine years of continuous research and experimentation, he succeeded in producing electricity by ‘converting magnetism’. In 1831, he formulated